Successfully changed filament, mid-print, on the fly, no major issues  

Successfully changed filament, mid-print, on the fly, no major issues

I thought there was a thread that discussed just this, but I could not find it.

I'm one who likes to use up spools of filament, as much as is practical, but like many of you I've acquired quite a collection of misc. tag ends, mostly in one of the dryboxes as loose coils, or else wound on smaller spools.

The 'official' method of changing a spool mid-print (pause, unload, load, purge, resume) always seems to leave some significant cosmetic discontinuities.

I tried once some time ago to force the end of a new spool into the extruder as the old spool ran out, but the filament sensor triggered and I had to do it the old fashioned way.

Tonight I decided to try a new approach, as in temporarily turn off the filament sensor.

As the tail end of the old spool disappeared into the extruder, I carefully fed the head end of the new spool behind it, with maybe about 6" of slack between my hand and the extruder, to allow for the print head movement.

Sure enough, the gears grabbed the new filament and fed it in following the old filament.

There is a discontinuity, in the change from one shade of brown to another, but in this case (O scale model railroad 'fill in' ties) the exact shade is not that important and is not obvious from a normal viewing distance.  I could not get the same brand of brown filament when I reordered.  No zits, blobs, cracks, streamers, etc.

Anyway, it's nice to know that such a technique is possible.

I just need to remember to turn the filament sensor off on the print where the spool change is going to occur, and, of course, to turn it back on for the next print.